The área of a rectangle with width 6 is 48 what is its length

Let x = length and y = width

Then, 2x+2y = 28 and xy = 48

Since 2x+2y = 28, y = 14 - x

So, x(14 - x) = 48

x2 - 14x + 48 = 0

(x-8)(x-6) = 0

x = 8 or x = 6

The rectangle is 8 ft by 6 ft. I hope

i'm not sure i quite understand, could you provide more information?

yes because there is exactly one y value for every x value

for function there can't be more than one value for every x value